Dr. Nina Kraus of Northwestern University has found a biological marker in the neural processing of sound that will help with the diagnosis and management of concussion. Her research – released in the journal Nature in December of 2016 – showed different brain activity when exposed to auditory stimuli between children who had experienced concussions compared to those who had not. By zeroing in on one very specific biomarker, the frequency-following response, her team could accurately diagnose concussion in 90% of children with concussion and confirm with 95% accuracy those in the control group who had not experienced concussion.
The frequency-following response, aka the auditory brainstem response to complex sounds, relates to the brain’s ability to respond to pitch. Those with concussion had an average 35% smaller response to pitch. And within the concussion group, those with the highest reported symptoms also had the smallest response to the fundamental frequency of speech. Not only was the response to pitch smaller, but it was also slower and less accurate in those participants who had suffered a concussion.
The researchers also found that as concussion symptoms abate, the response to pitch improved comparably. This proved their hypothesis that if sound processing is disrupted by concussion, it should also improve during the course of recovery.
The auditory system is at the nexus of the cognitive, sensory and limbic systems. Located in the midbrain, auditory processing is affected by both ascending and descending inputs from multiple neural systems outside of the auditory system. This makes it an ideal candidate for assessing effects of concussion that may occur anywhere in the brain. While concussions produce a variety of symptoms across multiple neural systems, this new assessment provides an objective measure that is not dependent on the subject’s effort or truthfulness in reporting.
The iLs Focus Series is regularly used to address symptoms of concussion. These three case studies focus on users with very different presentations:
52 year-old man “J” who sustained TBIs in two different car accidents
13 year-old boy “JN” who experienced a brain injury as a 3 year-old
60 year-old woman with brain stem injury who was able to return to social situations and improved her auditory processing
Learn more about the iLs family of tools.